/**
 * openHAB, the open Home Automation Bus.
 * Copyright (C) 2011, openHAB.org <admin@openhab.org>
 *
 * See the contributors.txt file in the distribution for a
 * full listing of individual contributors.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see <http://www.gnu.org/licenses>.
 *
 * Additional permission under GNU GPL version 3 section 7
 *
 * If you modify this Program, or any covered work, by linking or
 * combining it with Eclipse (or a modified version of that library),
 * containing parts covered by the terms of the Eclipse Public License
 * (EPL), the licensors of this Program grant you additional permission
 * to convey the resulting work.
 */

package org.openhab.core.internal.events;

import static org.openhab.core.events.EventConstants.TOPIC_PREFIX;
import static org.openhab.core.events.EventConstants.TOPIC_SEPERATOR;

import java.util.Dictionary;
import java.util.Hashtable;

import org.openhab.core.events.EventPublisher;
import org.openhab.core.types.Command;
import org.openhab.core.types.EventType;
import org.openhab.core.types.State;
import org.osgi.service.event.Event;
import org.osgi.service.event.EventAdmin;

/**
 * This is the main implementation of the {@link EventPublisher} interface.
 * Through it, openHAB events can be sent to the OSGi EventAdmin service
 * in order to broadcast them.
 * 
 * @author Kai Kreuzer
 *
 */
public class EventPublisherImpl implements EventPublisher {
		
	private EventAdmin eventAdmin;

	public void setEventAdmin(EventAdmin eventAdmin) {
		this.eventAdmin = eventAdmin;
	}

	public void unsetEventAdmin(EventAdmin eventAdmin) {
		this.eventAdmin = null;
	}

	/* (non-Javadoc)
	 * @see org.openhab.core.internal.events.EventPublisher#sendCommand(org.openhab.core.items.GenericItem, org.openhab.core.datatypes.DataType)
	 */
	public void sendCommand(String itemName, Command command) {
		if(eventAdmin!=null) eventAdmin.sendEvent(createCommandEvent(itemName, command));
	}

	/* (non-Javadoc)
	 * @see org.openhab.core.internal.events.EventPublisher#postCommand(org.openhab.core.items.GenericItem, org.openhab.core.datatypes.DataType)
	 */
	public void postCommand(String itemName, Command command) {
		if(eventAdmin!=null) eventAdmin.postEvent(createCommandEvent(itemName, command));
	}

	/* (non-Javadoc)
	 * @see org.openhab.core.internal.events.EventPublisher#postUpdate(org.openhab.core.items.GenericItem, org.openhab.core.datatypes.DataType)
	 */
	public void postUpdate(String itemName, State newState) {
		if(eventAdmin!=null) eventAdmin.postEvent(createUpdateEvent(itemName, newState));
	}
	
	private Event createUpdateEvent(String itemName, State newState) {
		Dictionary<String, Object> properties = new Hashtable<String, Object>();
		properties.put("item", itemName);
		properties.put("state", newState);
		return new Event(createTopic(EventType.UPDATE, itemName), properties);
	}

	private Event createCommandEvent(String itemName, Command command) {
		Dictionary<String, Object> properties = new Hashtable<String, Object>();
		properties.put("item", itemName);
		properties.put("command", command);
		return new Event(createTopic(EventType.COMMAND, itemName) , properties);
	}

	private String createTopic(EventType type, String itemName) {
		return TOPIC_PREFIX + TOPIC_SEPERATOR + type + TOPIC_SEPERATOR + itemName;
	}
}
